The present invention relates to a waste plastics separator which sorts plastic bottles and hard plastics having a shape similar to that of plastic bottle such as toys, which are resource refuse, in waste plastics by material and color.
Conventionally, it is well known that the near infrared rays absorption spectrum of plastics is peculiar according to the material thereof. In Europe including environmentally advanced nations, an automatic separator for waste plastic bottles using a measuring device for identifying material by utilizing the near infrared rays absorbing spectrum has been developed formerly and has been brought into commercial production (JP-A-9-220532). In Japan as well, technical development relating to such a technology has been rendered intensively, and some technologies have been published (JP-A-8-1101, JP-A-9-89768, and JP-A-9-220532).
Regarding the speed of measurement of the material of plastics using the near infrared rays absorption spectrum, a technology providing a speed less than 0.01 second per one spot has been developed by means of a spectrophotometry system using a combination of a near infrared spectral element and a one-dimensional solid-state image pickup element capable of being used in a near infrared zone. Also, the measurement of color of plastics has come to be capable of being made in a very short period of time. Therefore, the throughput of an automatic separator for waste plastic bottles etc. depends on the speed at which the plastic bottles etc. that have been charged disorderly are placed in a row.
However, the waste plastic bottles etc. are often pressed and collapsed into a flat shape, and moreover they are light in weight, so that it is very difficult to place them in a row. Therefore, the automatic separator for waste plastic bottles etc. has a problem in that because of the difficulty in placing them in a row, it is difficult to increase the throughput of the system, and also the system is complicate in construction.
It is an object of the present invention to provide a waste plastics sorting method and a separator that are capable of significantly increasing the efficiency of sorting waste plastics.
To achieve the object, firstly, the present invention provides a waste plastics separator comprising:
first alignment means for arranging waste plastics in a row in the lengthwise direction of waste plastics;
charging means for charging the waste plastics into the first alignment means;
second alignment means for selecting and discharging waste plastics which are not arranged in a row by the first alignment means;
detection means for detecting the waste plastics arranged in a row by the second alignment means;
sorting means for sorting the waste plastics arranged in a row by the second alignment means; and
sorting control means for controlling sorting work performed by the sorting means according to information detected by the detection means.
Secondly, the present invention provides a waste plastics separator comprising:
a sorting conveyor for conveying waste plastics;
a material identifying device for identifying the material of waste plastics on the sorting conveyor;
projected area increasing means for increasing the projected area of waste plastics entering into a material identification range of the material identifying device; and
delivering means for delivering waste plastics on the sorting conveyor at a predetermined position.
Thirdly, the present invention provides a waste plastics material identifying method comprising the steps of:
providing an inspection device in a halfway position of a conveying device for plastics;
eliminating any plastic being conveyed by plastics eliminating means on the upstream side of the inspection device and thereby forming a space in which no plastic exists on the conveying device;
obtaining a reference value by the inspection device in a space in which no plastic exists;
obtaining a measured value with a plastic by the inspection device in a space in which a plastic exists; and
identifying the material of plastic by comparing the measured value with the reference value.
Fourthly, the present invention provides a waste plastics material identifying device comprising:
a conveying device for plastics;
an inspection device provided in a halfway position of the conveying device to identify the material of plastics; and
plastics eliminating means provided on the upstream side of the inspection device in the conveying direction to eliminate any plastic being conveyed from the conveying device, in which any plastic being conveyed is eliminated by plastics eliminating means on the upstream side of the inspection device, and thereby a space in which no plastic exists is formed on the conveying device.
Fifthly, the present invention provides a waste plastics material identifying device comprising:
a light source for radiating light including near infrared rays;
a reflecting plate disposed substantially at right angles to the light axis of the light source so as to hold a waste plastic whose material is to be identified between the reflecting plate and the light source, the reflecting surface thereof being formed with irregularities;
a spectroscope for the spectrometry of near infrared rays which are radiated from the light source and are reflected by the waste plastic or the reflecting plate; and
an arithmetic unit for determining the material of the waste plastic based on the spectrometry result of the spectroscope.
Sixthly, the present invention provides a sorting device comprising:
a conveying device for conveying articles by a conveyor;
a compressed air injection nozzle disposed at the side of the conveying device over the length in the conveying direction of the conveying device to inject compressed air onto an article on the conveyor conveying surface of the conveying device from the side of the conveying device; and
means for recovering an article which is blown off by the injection.